Stress field evolution law of mining environment reconstructing structure with change of filling height

For improving global stability of mining environment reconstructing structure, the stress field evolution law of the structure with the filling height change of low-grade backfill was studied by ADINA finite element analysis code. Three kinds of filling schemes were designed and calculated, in which the filling heights were 2, 4, and 7 m, separately. The results show that there are some rules in the stress field with the increase of the filling height as follows: (1) the maximum value of tension stress of the roof decreases gradually, and stress conditions are improved gradually; (2) the tension stress status in the vertical pillar is transformed into the compressive stress status, and the carrying capacity is improved gradually; however, when the filling height is beyond 2.8 m, the carrying capacity of the vertical pillar grows very slowly, so, there is little significance to continue to fill the low-grade backfill; (3) the bottom pillar suffers the squeezing action from the vertical pillars at first and then the gravity action of the low-grade backfill, and the maximum value of tension stress of the bottom pillar firstly increases and then decreases. Considering the economic factor, security and other factors, the low-grade backfill has the most reasonable height (2.8 m) in the scope of all filling height.